Will acid damage Giallo Siena marble?
Yes, and permanently.
Answer
Does Giallo Siena marble scratch easily?
Keeping the surface
Stone does not scratch easily, but it does mark, and on a polished Giallo Siena marble surface a mark cannot be polished out without taking the whole polish with it. The risk is not the stone and a knife; it is grit and a dragging chair.
The figures
| Property | Value | Source |
|---|---|---|
| Mohs hardness | 6.5 on the published scale | Published technical sheet |
| Compressive strength | 89.4 to 175 MPa (published values across sources) | EN 1926-07 |
| Flexural strength | 21.2 to 25.3 MPa (published values across sources) | EN 12372-07 |
| Mark that cannot be polished out alone | A mark on a polished face requires the whole polish to be redone | Published maintenance practice |
Why this stone behaves this way
Marble is a hard stone and a soft polish at the same time. The hardness is in the crystal; the gloss is a surface layer a few microns thick, and that is what a dragged chair leg or a grain of sand finds first.
What these figures are, and what they are not Mohs 6 is published for the material. It says the stone resists a scratch; it does not say a polished surface resists an abrasive dragged across it, and the published values disagree on compressive strength by almost a factor of two.
Where these figures come from
- S1 granitalsiena.com — Giallo Siena marble technical sheet (EN standard test values; Politecnico di Torino marble laboratory)
- S6 StoneContact — Giallo Siena Unito and Broccatello di Siena entries, carrying Università di Pisa - Politecnico di Torino test values for the material
- S15 mggroupin.com — marble maintenance practice (sealing cycle, etching prevention)
Where to go next
On the same subject
More questions about Giallo Siena marble
How do you clean Giallo Siena marble?
With a soft cloth or a non-abrasive mop and a cleaner made for marble, neutral in pH.
This answer sits on the Keeping the surface page, with the rest of the questions about it.
Care and maintenanceAsk for a price
A thickness, a format, a finish, a quantity and a destination will get you a quotation for Giallo Siena marble.
Does Giallo Siena marble scratch easily?